For some beginning wind instrument students, however, D major is not a very good key, because it transposes to E major for B flat instruments. E major has four sharps, which is harder for new learners to play.

Still, the clarinet in B-flat is often used for music in D major. It is probably the key with the most sharps that it can play well. However, when some composers write a piece in D minor with B-flat clarinets, they change to clarinets in A if the music changes to D major.

After the valve trumpet was invented, composers began to write for trumpet in keys with more flats, so Haydn wrote his famous trumpet concerto in the key of E-flat major.

23 of Haydn's 104 symphonies are in D major, making it the most often used main key of his symphonies. A great number of Mozart's unnumbered symphonies are in D major, namely K. 66c, 81/73, 97/73m, 95/73n, 120/111a and 161/163/141a. The symphony came from the overture, and "D major was by far the most common key for overtures in the second half of the eighteenth century."[2]

Scriabin saw D major as golden in color and when he talked to Rimsky-Korsakov, he gave an example from one of Rimsky-Korsakov's own operas where a character sang in D major about gold.

↑Rita Steblin: A History of Key Characteristics in the Eighteenth and Early Nineteenth Centuries (Rochester, University of Rochester Press: 1996) p. 124 "The key of triumph, of Hallelujahs, of war-cries, of victory-rejoicing."